Cam profiling machine



Dec. M, 1948. c. PERRY CAM PROFILING MACHINE Filed July 11, 1944 2 Shee'ts-She et 1 4 INUENTOK. l CIA/Ami: Femay 2 Sheets-Sheet 2 C. PERRY CAM PROFILING MACHINE Dec; 14* 1948.

Filed July 11, 1944 G/MflfiSPf/P/Ey By 1 '4'// O 4-&

Agents Patented Dec. 14, 1948 CAM PROFILING MACHINE Charles Perry, Bexley, England, assignor to Vickers-Armstrongs Limited, London, England, a company of Great Britain Application July 11, 1944, Serial No. 544,414 In Great Britain November 23, 1943 9 Claims.

This invention relates to cam profiling machines of the type according to which a peripheral cam is cut on the principle of the relative movement of intersecting circles that represent paths of revolution of points on surfaces of rotatin members, a rotating rotary cutter being fed into the periphery of a rotating cam or cam blank, such movement being guided by a master cam, and means being provided to vary as desired the radius vectors both circumferential and axial of the cam thus cut.

The object of the invention is to provide an improved cam profiling machine giving certain important operational advantages that are obtained by virtue of an improved manner of mounting and guiding the cutting tool or tools.

In order that the invention may be clearly understood and readily carried into effect, one embodiment thereof will now be fully described with reference to the accompanying drawings, in which:

Figure 1 represents a front elevation of a cam profiling machine in accordance with the invention;

Figure 2 represents a planof the same machine;

Figure 3 represents a side sectional elevation of part only of the same machine on the line III-III of Figure 2; and

Figure 4 represents a side sectional elevation on the line IV-IV of Figure 2.

Figure 5 is a section on the line V-V of Figure 2.

A fixed base I I is provided with means for supporting a master cam I2 and a cam blank I 3, both these cam members being mounted and secured on a cam mandrel I4 rotatably supported on the base I I, being journalled in bearing-heads I5, I-6 integral with the base I I (or rigidly associated there-' Supported in the bearing-heads I5, I8 and par allel to the cam mandrel I4 is a cutter-frame axle I9 upon which a swinging cutter-frame 20 is arranged to pivot by means of flanges 2|, 22 suitably bored to receive bearing bushes 23, 24 in which the cutter-frame axle I9 is a sliding fit. In the present instance the cutter-frame axle I9 is journalled in fixed bearings in the bearingheads I5, I8. Preferably, however, the cutterframe axle I9 is supported by means that make it adjustable transversely of its axis both vertically and horizontally in respect of the cam mandrel I4. To this end the cutter-frame axle I9 may be journalled in rotatable eccentric bearing bushes suitably supported in the bearing-head I5, I I},

Thus it can be initially set to the best position relative to the maximum and minimum radius vectors of a cam to be cut, and can afterwards be adjusted so that any cutter it carries is moved 1ongitudinally to alter the place where the cutter makes contact with the work, after a used portion of the cutting edges has become dull.

The flanges H, 22 depend from the cutterframe 20 below the hinder part 25 thereof, which part is substantially of plate-like form and is bored from back to front with two holes adapted to accommodate respectively a tracing guide roller spindle 26 and a cutter spindle 21 which are parallel one to the other and on the front ends of which are carried respectively a tracing guide roller 28 and a rotary milling cutter 29. The tracing guide roller 28 and the cutter 29 are of the same diameter, and in the present case they are cylindrical, though they need not be so, provided that they are of circular cross-section throughout. The tracing guide roller spindle 26 and the cutter spindle 21 are preferably arranged to be initially adjustable longitudinally relatively to the axis of the cam mandrel I4, so as to enable cams with difierent rangesof axial profile to be accommodated. Instead of the tracing guide roller 28 a fixed tracing guide member could be used, formed as a solid of revolution or a portion of such a solid (say asegment thereof) it could for example be a member of circular cross-section rigidly mounted upon the tracing guide roller spindle 26 or such a member formed integral with that spindle; but a roller is preferred as introducing less friction.

The front part of the cutter-frame Z0 is formed as an arch 30 in the front limb or Wall 3| of which the front ends of the tracing guide roller spindle 2B and the cutter spindle 21 are suitably journalled. These front ends need not necessarily be thus supported, provided the respective spindles are adequately supported in the cutter-frame 2B.

In the present embodiment of the invention the axes of the tracing guide roller spindle 26 and the cutter spindle 2'! are arranged at right angles to the axis of the cam mandrel I4, but for the cutting of cams of certain profiles it is more convenient to provide an arrangement other than=right-angular. Provision may be made to allow of the two spindles being readily adjustable in respect of their inclination to the cam mandrel I4.

For the driving of the cutter 29 a flexible drive may be adopted, but it is preferred to provide an electric motor 32 mounted upon the hinder part 25 of the cutter-frame 20 centrally over the cutter- .frl'ame axle IS. The shaft 33 of the motor 32 is provided at its outer end with a small gear wheel 34 rigidly mounted on the shaft 33 and meshing with a larger gear wheel 35 rigidly mounted on the outer end of the cutter spindle 2'l.

Gravity alone may be used for feeding a cutter radially into a cam blank, the cutter-frame 2!! being so mounted upon the cutter-frame axle is that when the cutter-frame 20 is thrown forward so that the cutter 29 meets the cam blank IS the weight of the cutter-frame 2B and associated members pivoting upon the cutter-frame axle l9" provides the requisite force, until, when the cutting at any point is completed, the cutter-frame 29' becomes supported by tracing guide roller 28 upon the master cam l2. The said weight may be partly balanced by a counter-weight. v

Instead of thus utilising gravity for the radial feeding or a cutter, a spring or weight maybe suitably associated with the cutter-frame Zll to serve the same purpose, the force applied being made adjustable.

The invention is not limited to the use of a single cam blank upon the cam mandrel l2; a plurality of cam blanks may be tooled simultaneously if a plurality of milling cutters are provided correspondingly, one cutter to each cam blank to be tooled.

In order that the cutter 28 may be caused to traverse the cam blank 13 for the profiling of the latter, the cutter-irame 26 has to be appropriately moved longitudinally of the cam mandrel I4. For this purpose a feed screw 35 is provided, being rotatably supported in. the bearing-heads l5, l8 and being arranged directly below and parallelto the cutter-frame axle l9. Threaded upon the 1..

feed screw 36 is a nut 31 which is a link-like member arranged vertically in respect of its greatest dimension and of rectangular horizontal, crosssection, its. lower end being bored and internally screw-threaded to correspond to the feed screw 36, and its upper end being bored with a hole inwhich (or in a bush in. which) the cutter-frame axle i9 is a sliding fit. The nut 31 is or such a width (measured longitudinally of the cutter- :Erame axle I9) thatit fits slidingly between the flanges 2| and 22, or more particularly the bearing bushes 23", 24, so that rotation of the feed screw- 36 in one direction or the other causes motion of the cutter-frame 2'0 to left or right respectively without play,

A hand-wheel 38 with handle 39 is rigidly mounted on one end of the feed screw 36 in order that the cutter-frame 20 with cutter 29 may be fed by hand for the purpose of adjustment, or'onoccasion for the purpose of profiling a cam by hand.

Generally, however, the use of automatic power feed is preferred, as this is more uniform as well as being far more economical and convenient than feeding by hand. In order to provide power feed in the present instance the feed screw 36 is provided at its end remote from the hand-wheel 38 with a gear-wheel 40 which is rigidly affixed to the feed screw 3'5 and is associated with reduction gearing through which it is driven from a prime mover, in this case an electric motor. The gear-wheel ie meshes with a pinion M suitably supported on a shaft 42, the pinion 4| being integral with a gear-wheel 43 on the same shaft, which gear-wheel 43 inturn meshes with a pinion 44 rigidly mounted on the cam mandrel I4 or an extension thereof. A suitableelectric motor (not shown), preferably provided with worm gearing for speed-reduction, may be arranged to drive either the shaft 42 or the cam mandrel HS, in

4 order that both the feed screw 35 and the cam mandrel M may be driven simultaneously at predetermined relative speeds.

By this means the cam mandrel Hi is driven through variable-speed gearing so arranged that the rotational speed of the mandrel can be varied independently of the speeds of the cutter 29 and the feed screw 36.

A cam profiling machine as hereinbefore described may be modified so as to comprise automatic micrometrical means for making dimensional comparisons between a cam that is cut or partl-ycut and the master cam while the said cam and master cam are in situ in the machine. On the cutter-frame may be provided a fixed contact point adapted'to be brought to bear upon the mastercam, whilst a correspondingly adjusted contact point may be provided in relation to the said cam, this latter contact point forming part of a self-registering micrometer. Thus by direct readings of the micrometer the said dimensional comparisons can readily be made in respect either of the circumferential curvature of cams or (by performing appropriate traverses) of the lateral curvature thereof,

To this-end in the present embodiment of the invention the arch 30' of the cutter-frame 2B is drilled with two vertical holes 45, it-provided respectively with bushes ll, 48 in order that the said fixed contactpoint and the said contact point forming part of a self-registering micrometer may conveniently be applied. Of these two contact points theformer' is the end of a contact rod adapted to fit tightly but so as to be capable of vertical adjustment-within the bushes 4'1; and the latter is the'end of the plunger of a micrometer, which instrument comprises a dial (preferably graduated in thousandths and half thousandths of aninch) rigid-1y associated with a cylindrical s'hank 'adapted to fit tightly but so as to-be capable of vertical adjustment within the bushes 48, within which shank the said plunger is longitudinally movable, its longitudinal motion being accompanied by corresponding radial movement of a pointerassoeiated-withthe saiddi-a-l.

In order to apply the said two contact points, the tracing guide roller 25 and the cutter 29- with their respective spindles 26, 2? are first removed so to provide unobstructedacce'ss from above to the master cam 82 and the cam blank l3 (whichisthe said cam that is cut or partly-cut). The said rod is then pressed downwards into the bushes ll until, when the cutter-frame 2B is substantially horizontal, the rod rests'upon the mastercam l2 and in this way supports the cutter-frame 26, Next the said shank of the micrometer is pressed-downwards into the bushes 48- until the said plunger makes contactwith thc cam blank t3 and is slightly pushed back into the shank, a certain reading of the micrometer pointer being accordingly registered. The particular reading islnot in itself of consequence, as what is-requ-ired= is-rnerely an indication of anydeviations from uniformity.

" If new the machine is actuated so that the cutter-frame 2-53 isfcd'longitudinall 'of the master cam t2 and the cam blank 13, these cams being simultaneously rotated, the contact point of the contact rod will follow the profile of the master cam l 2, and the cutter-frame Zilwill move up and down correspondingly; In case the cam blank it has been profiled to be an exact replica of the :masterearn 1 2 there will be nomovement of the mi erometer plung er, and consequently no variation of the dial" reading. a If any variation ofreading occurs, this variation will indicate and measure the amount of discrepancy of profile between the cam that has been cut and the master cam.

By the mounting and guiding of the cutting tool or tools of a cam profiling machine in the manner hereinbefore described, at least four outstanding advantages are obtained, namely: (1) cams of the kind produced by the machine can be accurately cut to any desired size and profile from a master cam, the diameter of the cutter and contact roller being of course varied according to the size of cam to be cut; (2) the said micrometrical means enables dimensional comparisons to be made quickly and accurately between any cam that is being cut and the master cam; (3) the provision ofthe said variablespeed gearing introduces automatic means to maintain substantially constant the peripheral speed of a cam blank relatively to the cutter; and (4) a machine according to the invention lends itself to the cutting of a number of cams simultaneously, the number that can be thus out being limited only by the need for maintaining sufficient rigidity in the machine and by the requirements of apredetermined degree of accuracy in the cams produced.

What I claim is:

1. A cam profiling machine of the type described and comprising a cutter-frame provided with a plurality of operative members arranged with their axes parallel to one another, at least one of which members is a rotary cutter and at least one other of which members is a tracing guide member formed as at least a portion of a solid of revolution of the same general shape as the said rotary cutter and being of substantially the same radius as the cutter, the said cutterframe being associated with a base provided with means for supporting upon a common axis a master cam and a cam blank in such a manner as to render them rotatable simultaneously at the same angular speed, the arrangement being such that the said operative members when in any operative position bridge the said master cam and cam blank respectively so as to be adapted to rest transversely upon them, the parallel axes of the operative members always being in a different plane than said common axis of the master cam and cam blank, the cutterframe being provided with feeding means adapted to move it axially of the said master cam and the said cam blank, and the cutter frame being also associated with guiding means enabling it to fioat to such an extent as to make the said tracing guide member and cutter freely movable in the direction to and from the master cam and cam blank but substantially immovable in all other directions except as moved by the said feeding means, the cutter-frame and the cutter and the tracing guide member being so arranged in relation to the said base and to each other that, when the master cam and cam blank are in situ supported upon the base, by floating motion of the cutter-frame the cutter can be caused to approach the cam blank so as to operate upon it, and the tracing guide member be simultaneously and correspondingly caused to approach the master cam in such a manner that by cooperation between the tracing guide member and the master cam during the operation of the machine the cutter is limited and guided in its approach to the cam blank so that the cam blank is cut to a profile that corresponds to the profile of the master cam.

2. A cam profiling machine according to claim 1 and in which the said tracing guide member is of circular cross-section, as for example a roller adapted to revolve upon a spindle that carries it.

3. A cam profiling machine according to claim 1 and in which the said feeding means comprise a feed screw rotatably supported upon the said base and engaging with a nut suitably associated with the said cutter-frame.

4. A cam profiling machine according to claim 1 and in which the said guiding means comprise a cutter-frame axle supported upon the said base and arranged parallel to the said feed screw, upon which cutter-frameaxle the said cutter-frame is arranged to pivot, the cutter-frame axle being disposed adjacent to the plane common to the axes of the said tracing guide member and the said rotary cutter but at a distance from these members longitudinally thereof.

5. A cam profiling machine according to claim 1 and in which the said guiding means comprise a cutter-frame axle supported upon the said base and arranged parallel to the said feed screw, upon which cutter-frame axle the said cutter-frame is arranged to pivot, the cutter-frame axle being disposed adjacent to the plane common to the axes of the said tracing guide member and the said rotary cutter but at a a distance from these members longitudinally thereof, and the said profiling machine having its parts so constructed and arranged that the weight of the said cutterframe and associated members pivoting upon the cutter-frame axle provides the requisite force for feeding a cutter radially into a cam blank.

6. A cam profiling machine according to claim 1 and in which the said guiding means comprise a cutter-frame axle supported upon the said base and arranged parallel to the said feed screw, upon which cutter-frame axle the said cutter-frame is arranged to pivot, the cutter-frame axle being disposed adjacent to the plane common to the axes of the said tracing guide member and the said rotary cutter but at a distance from these members longitudinally thereof, and the said means for supporting a master cam and cam blank and rotating them simultaneously comprising a cam mandrel upon which both these cam members are mounted and secured, the said cam mandrel being rotatably supported on the said base and being arranged parallel to the said cutter-frame axle.

7. A cam profiling machine according to claim 1 and in which the said guiding means comprise a cutter-frame axle supported upon the said base and arranged parallel to the said feed screw, upon which cutter-frame axle the said cutter-frame is arranged to pivot, the cutter-frame axle being disposed adjacent to the plane common to the axes of the said tracing guide member and the said rotary cutter but at a distance from these members longitudinally thereof, and the said means for supporting a master cam and cam blank and rotating them simultaneously comprising a cam mandrel upon which both these cam members are mounted and secured, the said cam mandrel being rotatably supported on the said base and being arranged parallel to the said cutter-frame axle, and being driven by a suitable prime mover through variable-speed gearing so arranged that the rotational speed of the mandrel can be varied independently of the speeds of the said cutter and the said feed screw.

8. A cam profiling machine according to claim 1 and in which the said guiding means comprise a cutter-frame axle supported upon the said base and arranged: parallel to the said feed screw, upon which cutter-frame axle the said cutter-frame is arranged to pivot, the cutter-frame axle being disposed. adjacent to the plane common to the axes of the said tracing guide member and the saidv rotary cutter but at a distance from these members longitudinally thereof, and the said means for supporting a master cam and cam blank and rotating them simultaneously comprising a cam mandrel upon which both these cam members are mounted and secured, the said cam mandrel being rotatably supported on the said base and being arranged parallel to the said cutter-frarne axle, and being driven by a suitable prime mover through variable-speed gearing'so arranged that the rotational speed of the mandrel can be varied independently of the speeds of the said cutter and the said feed screw, the said feed screw being drivenby the same said prime mover through suitable gearing,

9. A cam profiling machine according to claim 1 and in which the said cutter-frame is pierced with two parallel rectilinear holes which, when the cutter-frame is in operative position are disposed substantially vertical and radial to the axis of the said cam mandrel, one of the said holes being so formed and disposed as to be adapted to hold rigidly a contact member comprising a fixed removed dimensional comparisons can be made between the cam and the. master cam while both are on the cam mandrel.

CHARLES PERRY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 467,596 Snow Jan. 26, 1892 1,798,926 Black Mar. 31, 1931 FOREIGN PATENTS Number Country Date 96,611 Germany Apr. 15, 1898 327,957 Germany Oct. 19, 1920 534,447 Germany Sept. 26, 1931 

